There is an ancient Chinese story about how giant pandas got their unique markings. A young girl who was a friend of these bears died and the pandas were struck with sorrow. They wept at the funeral and rubbed their eyes with their arms. The dark color from their arm bands was wiped onto their eyes. The bears then hugged themselves and marked their ears, shoulders, hind legs and rumps, resulting in the pattern seen today. The classification of A. melanoleuca has been a difficult one for researchers to agree upon. Giant pandas have several characteristics in common, like bamboo eating, with red pandas, who have sometimes been considered to be members of the raccoon family (but currently are also classified with bears). Today it is widely accepted with little doubt that that giant pandas belong to the bear family (Ward and Kynaston, 1995).
Formerly these pandas were found in hilly ravines at lower elevations, but populations have been forced into the mountains and they can now be found in temperate montane forest at 1,200 to 3,400 metres, where there is an abundance of bamboo (4).
Giant pandas have an extremely strict energy budget. They travel little and are usually foraging when they do move. Giant pandas can spend 10-12 hours a day feeding. Bamboo, the main source of pandas' diet (over 99%) is a very poor nutritional source but present all year round. Only about 17% of the nutrients found in the leaves and stalks are extracted. These bears make a trade-off to have a plentiful, easily obtained food source but with low nutritional value. Giant pandas are well-known for their upright feeding position which leaves their forelegs free to handle the bamboo stalks. This species has several special characteristics related to eating bamboo. The extra digit on the panda's hand helps the panda in tearing the bamboo. This adaptation also allows increased dexterity while handling bamboo. The stomach walls are extremely muscular to help digest the woody diet; and the gut is covered with a thick layer of mucus to protect against splinters (Ward and Kynaston, 1995; Malius, 2001; Massicot, 2001).
Foods eaten include: bamboo stems and shoots, fruits of plant matter like kiwi, small mammals, fish and insects.
Three range-wide surveys have been conducted, in the mid-1970s, mid-late1980s, and 20002002. All surveys were based on incidence of sign, but techniques varied, so results are not directly comparable. Present best estimates indicate a total wild population between 1,0002,000. Greater protection of forests and from poaching in recent years suggest that panda populations should be increasing, but this has not been confirmed empirically.
Results from the most recent survey, coordinated by the State Forestry Administration (SFA) of China and World Wildlife Fund (WWF), indicated a total population of ~1600 individuals. This is over 40% higher than previous estimates. It is believed that the increase in the estimated number of pandas is due largely to differences in survey methodology and a larger search area, as well as possibly an actual increase in panda population size in some areas. Conversely, in other areas, habitat conditions were deemed to be worse and panda numbers lower in 20002002 than in the 1980s survey.
The most recent population estimate was based on differentiating individual pandas from measurements of bamboo fragments in scats. It is known that different age classes of pandas have different bite-sizes of bamboo (Schaller et al. 1985), but the validity of differentiating individuals of the same age class based on bite-sizes has not been well tested. Recent information on DNA-identified scats suggests that the bite-size method may underestimate population size in some cases (e.g., dense populations; Zhan et al. 2006).
Many surviving wild giant panda subpopulations have fewer than 50 individuals (Loucks et al. 2001). No major reductions in the genetic diversity of these populations is apparent, although they likely experienced modest genetic losses from a much larger ancestral population (L 2001). Some controversial research suggests that the Qinling (Shaanxi Province) population is a genetically isolated and distinct subspecies (Wan et al. 2005)
Adults of this solitary species have well-defined home ranges and rarely meet, except in the mating season that runs from March to May (5). During this time, pandas signal their presence by marking trees and banks with scent secreted from glands located beneath the tail (6). They will also strip bark and occasionally males will dust bathe; dust particles become covered with the pandas' scent and then waft into the air (6). Males also call during this time, and these can be heard echoing through the mountains (7). Females give birth to a single cub that is born in an extremely immature stage of development; weighing only a tiny fraction (0.001%) of their mother's weight (5). The female cares for her cub in a den located in the base of a hollow tree or in a cave for the first few months of its life (4) (8). Young pandas remain dependent on their mother for a year, by which time they are weaned, but usually remain with their mothers until they are two years of age and sometimes longer (4) (8). During this time, females may leave their cubs to forage for days at a time and in the past these supposedly 'abandoned' cubs were taken into captivity (4). Pandas are unusual amongst the larger mammals for the extreme specialisation of their diet, which depends almost entirely on bamboo. Bamboo is a relatively abundant food source but has poor nutritional value; adults must spend around 14 hours a day feeding (4), and need to consume between 10 and 20 kg over 24 hours (8). They therefore alternate periods of feeding and resting throughout the day and night (7). Bamboo is evergreen and in winter pandas concentrate on leaves and stems, descending to lower altitudes in search of new shoots in spring (6). Despite their specialisation on bamboo, pandas will readily scavenge on meat should they come across it (7).
Giant panda population is closely tied to bamboo abundance and vice versa. Pandas help to distribute the bamboo seeds over areas. However, as panda numbers dwindle so does bamboo, making it harder for them to find food. Panda protected areas help to protect native ecosystems.
Ecosystem Impact: disperses seeds
World Wildlife Fund, 2001. "Endangered Species: Panda Conservation" (On-line). Accessed (Date Unknown) at http://www.worldwildlife.org/pandas/conservation.htm.
Restricted and degraded habitat is the greatest threat to giant pandas. Population fragmentation exists on two scales six mountain ranges separated by agriculture, and within these, fragments of bamboo forest separated by patches of cleared lands and forest without a bamboo understory. The giant panda's range contracted as trees were removed in logging operations and land was cleared for farming. Populations of pandas thereby became small and isolated, and confined to high ridges, hemmed in by cultivation.
Chinese authorities have established a network of panda reserves, and linkages now exist among some of these, but small population size and small total range remains a threat to the viability of this species. Moreover, in some reserves, and especially in panda range outside reserves, habitat has become degraded by intensive human use (Liu et al. 2001).
A further threat to pandas relates to their reliance on bamboo for food. Bamboo is subject to periodic, synchronous (and hence large-scale) flowering and die-off (at intervals of 15120 years). Before significant human encroachment of their habitat, pandas could move to areas with healthy bamboo when a die-off occurred. Studies following the latest major bamboo die-off in the early 1980s indicated that pandas were still able to survive by finding patches that had not flowered, and also by moving to alternate habitats and feeding on less-favoured species of bamboo (Johnson et al. 1988, Reid et al. 1989).
Poaching of pandas was a serious problem in the past, but it has greatly diminished, and is no longer considered a major threat. Markets for panda skins have virtually disappeared, and penalties for poaching pandas have become far more severe (including death sentences in some cases). Panda parts are not used in Traditional Chinese Medicine. However, giant pandas are still sometimes killed in snares set for musk deer and other species.
The black and white markings on giant pandas may have served as an anti-predator device in the past when the animals had predation pressure. The black and white pattern might have broken up the outline the bears presented, similar to the effect of zebra stripes. Also, in the past, when these pandas inhabited snowier areas, the white may have helped these bears blend into the surroundings. However, today giant pandas live in almost snow free areas. Fortunately no more natural predators exist for pandas today (Ward and Kynaston, 1995).
humans (Homo sapiens)
No natural enemies today but possibly in the past animals such as tigers
Habitat loss is the greatest cause of the decline of the giant panda. Large areas of China's natural forest have been cleared for agriculture, timber and firewood to meet the needs of the large and growing human population (4). Bamboo undergoes periodic dieback every 40 - 60 years and swathes of a species will disappear. Previously, pandas would migrate to find alternative bamboo sources; today however, only fragments of forest remain and this is no longer possible, causing populations to be even more vulnerable (7). Despite strong protection measures, pandas are still occassionally killed for their pelts and are accidentally captured in traps.